Tub having structually strengthened rear wall and washing machine with the same therein

ABSTRACT

A tub having a structurally strengthened rear wall and a washing machine with the same therein are disclosed. A washing machine includes a bearing housing having a flange part and a tub injection-molded with the bearing housing inserted into a wall thereof, the wall having a recessing part and a projecting part formed on an inner or an outer surface thereof along a circumferential direction, and a circumferential rib or a radial rib formed on the recessing part.

This application is a continuation-in-part of application Ser. No. 10-730281 filed on Dec. 9, 2003, which claims priority of Korean Patent Application 10-2002-0078337 and 10-2003-0086841 filed in Korea on Dec. 10, 2002 and on Dec. 2, 2003, respectively.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a tub having a structurally strengthened rear wall and a washing machine with the same therein, and more particularly, to a tub injection-molded with a bearing housing inserted supporting a shaft to rotate a drum.

2. Discussion of the Related Art

In general, a washing machine is an apparatus which washes laundry by automatically performs a washing, rinsing and spinning cycle. After the laundry and detergent are loaded into a drum, washing is performed by using friction force between the laundry and wash water. The washing machine is classified into a pulsator type, an agitating type and drum type washing machine according to a washing method.

Especially, the drum type washing machine is classified into a drum type washing machine with an indirect-drive-motor and a drum type washing machine with a direct-drive-motor. The driving force of the indirect-drive-motor is indirectly transmitted to a drum through a belt wound around a motor pulley and a drum pulley. The driving force of the direct-drive-motor is directly transmitted to the drum, because a rotor of a BLDC motor is directly connected to the drum.

Referring to FIG. 1, a structure of a drum type washing machine with a direct-drive-motor will be schematically described as one example of the conventional washing machine.

As shown in FIG. 1, a tub 2 is mounted within a cabinet 1, and a drum 3 is rotatably mounted within the tub 2.

Also a motor having a stator 6 and a rotor 5 is mounted on a rear wall of the tub 2. The stator 6 is secured to the rear wall of the tub 2, and the rotor 5 surrounding the stator 6 is connected with a shaft. The shaft passes through the tub and is fastened to the drum 3.

A bearing housing of metal material is inserted into the rear wall of the tub 2 to support the shaft. The tub 2 is manufactured by injection-molding process with the bearing housing inserted in the mold.

FIG. 2 illustrates a conventional tub 2, more specifically, an outer surface of the rear wall where the motor is mounted.

As shown in FIG. 2, a circumferential rib 11 and 12 is formed in a circumferential direction on the outer surface of the rear wall of the tub 2, and a radial rib 21 is also formed on the outer surface of the rear wall in a radial direction. The farther the radial rib 21 is from the center of the rear wall, the lower the height thereof is. Thus, the rear wall of the tub may have a problem in its strength and rigidity. Furthermore, the distance between the radial ribs is gradually getting wider from the center thereof. Thereby, the strength of the rear wall of the tub is not high enough and it causes a structural-strength-related problem in the farthest portion of the rear wall from the center.

Also, the thickness between the circumferential rib 11 formed nearer to the center of the rear wall and the circumferential rib 12 formed farther from the center is the same. Since the nearer portion to the center is more affected by the vibration of the shaft than the farther portion, the nearer portion is needed to have much strength and rigidity. Nevertheless, the conventional washing machine fails to solve the above problem.

Moreover, according to the conventional washing machine, the circumferential rib 11 and 12 and the radial rib 21 are formed relatively high to enhance the strength of the rear wall of the tub. However, the higher the ribs are, the more flexible the ribs are. Thereby, the strength or rigidity is not gained as high as structurally required and it causes a structural-strength-related problem as well as high production cost.

Meanwhile, since the inner surface (not shown) of the rear wall of the tub is formed as a smooth surface without ribs, the reinforcement for the strength is dependent on the ribs on the outer surface only. That is one of the reasons why the ribs on the outer surface are high in the conventional washing machine.

The capacity of the tub for holding wash water therein influences the capacity of the washing machine. Here, the capacity of the tub is influenced by the position of the inner surface of the rear wall. Since the conventional rear wall of the tub described above has the inner surface thereof sided toward the drum, the conventional rear wall of the tub has a disadvantage that the tub has a small capacity.

Also, the overall thickness of the rear wall of the tub with the height of the rib considered may affect the disposition of the other components within the limited space of the cabinet.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a tub having a structurally strengthened rear wall and a washing machine with the same therein that substantially obviates one or more problems due to limitations and disadvantages of the related art.

An object of the present invention is to provide a tub having a structurally strengthened rear wall and a washing machine with the same therein, wherein the rear wall of the tub with a bearing housing inserted therein has a recessing part and a projecting part along a circumferential direction and a flange part of the bearing housing has a recessing part and projecting part corresponding with the recessing part and the projecting part of the rear wall.

Another object of the present invention is to provide a tub manufactured by injection-molding process with a bearing housing inserted into the mold, wherein the tub does not cause a problem due to stress concentration especially in the place near to the outer end of the flange of the bearing housing.

A third object of the present invention is to provide a rear wall of a tub having a recessing part and a projecting part thereon for reinforcing the strength and rigidity. Especially, the ribs are formed on the recessing part to maintain the predetermined overall thickness of the rear wall of the tub, such that the disposition of other components and the capacity of the tub are not affected.

A fourth object of the present invention is to help a drum to rotate smoothly by thickening the circumferential rib nearest to the center of the rear wall and structurally strengthening the center portion affected by the vibration of the shaft most, such that the shaft is supported securely.

Recently, there have been demands for a washing machine with a large capacity. Also, the demands for a tub having a structurally strengthened rear wall have increased. Thus, the present invention is invented to satisfy the demands and to provide a rear wall of a tub having no problems of the related art in a washing machine with a large capacity.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention. The objectives and other advantages of the invention may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these objects and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, a washing machine comprising a bearing housing having a flange part; and a tub injection-molded with the bearing housing inserted into a wall thereof, the wall having a recessing part and a projecting part formed on an inner or an outer surface thereof along a circumferential direction, and a circumferential rib or a radial rib formed on the recessing part.

The wall of the tub, as shown in FIG. 1, is a rear wall in a front loading type washing machine, and a vertical wall of a left side or a right side in a top loading type washing. The wall is a portion where a bearing housing for supporting a shaft rotating a drum is inserted, regardless of any type of washing machines. The front loading type washing machine is presented as an example as follows, and the present invention may be applied to any type of washing machines included in the scope of the present invention.

According to the present invention, the bearing housing and the tub may be fastened securely, because the bearing housing is inserted into the rear wall of the tub. In addition, since the bearing housing has the flange part, the strength and rigidity of the rear wall of the tub can be enhanced by the flange part, and the tub and the bearing housing can be connected securely.

Furthermore, the strength and rigidity of the rear wall can be more enhanced, because the rear wall has the recessing part and the projecting part. The recessing part and the projecting part can be formed on an inner surface or an outer surface of the rear wall. Preferably, the recessing part and the projecting part are formed on the both of the inner and outer surface of the rear wall.

Here, a circumferential rib or a radial rib is formed on the recessing part in a circumferential direction to structurally strengthen the wall. Preferably, the circumferential rib and the radial rib are formed.

The present invention is invented through a lot of experiments and computer aided engineering. The inventor is motivated to find a problem of crack caused in case that a circumferential rib is provided on the same circumference as the circumference of an outer end of the flange part of the bearing housing. The inventor found that the biggest reason is the stress concentration on the end of the circumferential rib.

Therefore, it is preferred that the circumferential rib is spaced apart from an outer end of the flange part in a radial direction. That is, the circumferential rib is preferred not to be provided on the same circumference as the circumference of the outer end of the flange part.

Preferably, a circumferential rib or a radial rib is formed on the projecting part on the same circumference of the outer end of the flange part.

Especially, in case that the circumferential rib is provided on the same circumference as the circumference of the outer end of the flange part, the circumferential rib or the radial rib is more necessarily provided on the projecting part.

In connection with the structural strength, the correlation between the potion of the circumferential rib and the outer end of the flange part is found through many experiments and a process of trial and error, and the above technical solution has the most preferable result out of the various trials.

Moreover, preferably, the flange part of the bearing housing has a recessing part and a projecting part corresponding with the recessing part and the projecting part of the wall, respectively. It is more preferable that the flange part has an embossing appearance corresponding with the embossing appearance of the rear wall of the tub for the recessing and the projecting parts.

At least one portion of the radial rib formed on the recessing part of the wall is inclined upwardly from the center of the wall. Especially, as far as the strength is concerned, it is preferable that the inclined portion is a portion of the rear wall where the flange part is not inserted, since the portion where the flange part is inserted is reinforced enough by the flange part. That is, the farther outwardly from the outer end of the flange part, the higher the radial rib is.

Since the flange part is inserted into the near portion of the rear wall from the center and the distance between the radial ribs is narrow, the center portion of the rear wall is structurally strengthened. Whereas, the other portions are not strengthened enough. Thus, the strength is reinforced by heightening the radial rib.

Preferably, the circumferential rib and the radial rib formed on the recessing part of the wall of the tub cross. In case that they do not cross, the inventor found through the experiments and computer aided engineering that the stress is concentrated. Also, preferably, the height of the circumferential rib and the height of the radial rib are the same due to the same reason.

Since it is affected a lot by the vibration of the shaft, the inner center portion of the rear wall of the tub should be structurally strengthened. For that reason, the circumferential rib formed on the recessing part of the wall of the tub is provided in plural, and the circumferential rib nearest to the center is thicker than the other circumferential ribs.

The circumferential rib nearest to the center is formed in the same circumference as a circumference of a boss for allowing a stator fastened thereto.

Preferably, the flange part has a circumferential rib, and more preferably, the circumferential rib of the flange part is inserted into the nearest circumferential rib of the tub to the center

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this application, illustrate embodiment(s) of the invention and together with the description serve to explain the principle of the invention. In the drawings:

FIG. 1 is a diagram illustrating a conventional drum type washing machine according to the related art.

FIG. 2 is a diagram illustrating a conventional tub injection-molded with a bearing housing inserted therein.

FIG. 3 is a diagram illustrating an outer surface of a rear wall of a tub according to the present invention.

FIG. 4 is a diagram illustrating an inner surface of the rear wall of the tub in FIG. 3 according to the present invention.

FIG. 5 is a perspective view illustrating enlarged key parts of FIG. 3.

FIG. 6 is a sectional view illustrating that a motor is mounted in the tub of FIG. 3.

FIG. 7 is a diagram illustrating an outer surface center portion of a rear wall of a tub according to another embodiment of the present invention.

FIG. 8 is a diagram illustrating an inside of the tub in FIG. 7.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts.

Referring to FIGS. 3 to 6, a bearing housing 7 of metal material is inserted into a rear wall of a tub according to the present invention. The tub 2 is injection-molded by injecting plastic melt thereto after inserting the bearing housing into the tub 7.

A recessing part 120 and 220 and a projecting part 110 and 210 are formed on an inner surface or an outer surface of the rear wall of the tub 2. According to this embodiment of the present invention, the projecting part 110 of the outer surface of the rear wall is corresponding with the recessing part 220 of the inner surface thereof, whereas the recessing part 120 of the outer surface thereof is corresponding with the projection part 210 of the inner surface thereof. That is, the rear wall of the tub 2 has an embossing appearance formed along a circumferential direction. The above embossing appearance may enable the rear wall of the tub 2 to secure enough strength and rigidity, even though the rear wall is not so thick.

The bearing housing 7 inserted into the rear wall of the tub 2 has a flange part 8. The flange part 8 is also insertedly formed in an embossing appearance corresponding with the embossing appearance of the rear wall of the tub 2.

The circumferential ribs 121, 122, 123 and 124 and a radial rib 125 are crossed on the recessing part 120 of the outer surface of the rear wall of the tub. Also, the circumferential ribs 221, 222, 223 and 224 and the radial rib 225 are crossed on the recessing part 220 of the inner surface of the rear wall.

The circumferential ribs 121 and 221 nearest to the center of the rear wall of the tub 2 are thicker than the other circumferential ribs.

Here, a circumferential rib 81 is formed on the recessing part of the flange part 8 of the bearing housing 7, corresponding with the circumferential ribs 121-124 and 221-224 of the tub 2. The circumferential rib 81 of the flange part 8 is inserted into the circumferential rib 121 and 221 nearest to the center of the tub 2.

) Moreover, a boss 131 is formed on the rear wall of the tub 2 for fastening a stator 6 of a motor. The boss 131 is provided in the circumferential rib 81 of the flange part 8, and a hole of the boss 131 is exposed to the projecting part 110 of the outer surface of the rear wall.

The circumferential rib 121 and 221 nearest to the center out of the circumferential ribs 121-124 and 221-224 is provided in the same circumference as the circumference of the boss 131, such that the stator 6 fastened to the boss 131 is supported securely.

The circumferential ribs 121-124 and 221-224 of the recessing part 120 of the rear wall are spaced apart from an outer end of the flange part 8 in a radial direction. A circumference referenced to as a dotted line ‘A’ in FIGS. 3 and 4 is the portion where the outer end of the flange part 8 of the bearing housing 7 is positioned, and the circumferential ribs 121-124 and 221-224 are not on the circumference, but spaced apart from the outer end of the flange part. Thus, stress is prevented from being concentrated only on some part enough to cause crack, because the circumferential ribs 121-124 and 221-224 are not provided in the same position of the circumference of the outer end of the flange part 8.

Meanwhile, as shown in ‘B’ of FIG. 5, at least one portion of the radial rib 125 is inclined. The farther the radial rib is from the center, the higher the radial rib is inclined. As shown in FIG. 5, it is preferred that the inclined portion starts from the dotted ‘A’ portion. Since the portion where the flange part 8 is not inserted, especially, the portion farther from the center of the rear wall is weaker in the strength and rigidity, the strength and rigidity of the rear wall may be reinforced by heightening the rib.

The height of each circumferential rib 121-124 and 221-224 and the height of each radial rib 125 and 225 are the same in most portions thereof to prevent the stress from being concentrated only some part of the rear wall.

FIG. 6 illustrates a sectional view where the motor is mounted in the rear wall of the tub 2. The stator of the motor is fastened to the boss 131 of the rear wall of the tub 2 by a bolt, and a rotor 5 is connected with a shaft 4 and the shaft is connected with a drum 3.

Once the power is applied to the motor, the rotor 5 rotates to rotate the shaft 4. Hence, the drum 3 rotates. Since the drum is vibrated during the rotation, the vibration is transmitted to the rear wall of the tub through the shaft 4 and the bearing housing 7.

In case the number of rotor rotation is small due to the small capacity of the washing machine, the vibration of the drum 3 is also small. Thereby, the conventional rear wall of the tub is enough for the vibration. However, as recently the capacity of the washing machine has been getting larger, the number of the motor rotation is larger. Thus, there have been demands for a tub 2 having a structurally strengthened rear wall.

The rear wall of the tub 2 is invented through a process of trial and error to cause no problems in a state where the capacity of the washing machine is larger.

By the way, FIGS. 7 and 8 illustrate another embodiment of the present invention. Hereafter, only the different part from the above embodiment shown in FIG. 3 will be described.

Firstly, FIG. 7 illustrates an outer surface of a rear wall of a tub, and FIG. 8 illustrates an inner surface of the rear wall of the tub.

According another embodiment of the present invention, a circumferential rib 111 and 211 and a radial rib 112 and 212 are crossed on a projecting part 110 and 210. The ribs are provided on a circumference A where an outer end of a flange part 8 of a bearing housing 7 is provided. Thereby, the strength of the outer end of the flange part 8 of the bearing housing 7 may be reinforced.

In case that the circumferential rib 111 and 211 and the radial rib 112 and 212 are formed on the projecting part 110 and 210, the enough strength may be reinforced even when the circumferential ribs 121-124 and 221-224 formed on the recessing part 120 and 220 are provided on the circumference A.

Therefore, according to the present invention, the problems which the related art may cause will be solved.

Also, the rear wall of the tub injection-molded with the bearing housing inserted therein is structurally strengthened, because the recessing part and projecting part are formed on the rear wall of the rub along a circumferential direction. Here, the flange part of the bearing housing has the recessing part and the projecting part corresponding with the recessing part and the projecting part of the rear wall, such that the rear wall of the tub may be more structurally strengthened.

Furthermore, the strength and rigidity of the rear wall may be reinforced due to the circumferential rib and the radial rib formed on the rear wall of the tub. Especially, the ribs are formed on the recessing part. Thus, the thickness of the rear wall may be maintained and there may not be any problems related to disposition of the other components and tub capacity. Also, the rear wall of the tub may be gained, because the inventor proved the correlation between the circumferential rib position and the outer end of the flange part of the bearing housing.

The center portion of the rear wall affected by the vibration of the shaft may be structurally strengthened, because the circumferential rib nearest to the center of the rear wall is thicker than the other circumferential ribs, thereby, shaft being supported securely to rotate the drum smoothly.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions. Thus, it is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. 

1. A washing machine comprising: a bearing housing having a flange part; and a tub injection-molded with the bearing housing inserted into a wall thereof, the wall having a recessing part and a projecting part formed on an inner or an outer surface thereof along a circumferential direction, and a circumferential rib or a radial rib formed on the recessing part.
 2. The washing machine of claim 1, wherein the circumferential rib is spaced apart from an outer end of the flange part in a radial direction.
 3. The washing machine of claim 1, wherein a circumferential rib or a radial rib is formed on the projecting part in the same circumference of the end of the flange part.
 4. The washing machine of claim 2 or 3, wherein the flange part of the bearing housing has a recessing part and a projecting part corresponding with the recessing part and the projecting part of the wall, respectively.
 5. The washing machine of claim 4, wherein at least one portion of the radial rib formed on the recessing part of the wall is inclined upwardly from the center of the wall.
 6. The washing machine of claim 4, wherein the circumferential rib and the radial rib formed on the recessing part of the wall of the tub cross.
 7. The washing machine of claim 6, wherein the height of the circumferential rib and the height of the radial rib are the same.
 8. The washing machine of claim 4, wherein the circumferential rib formed on the recessing part of the wall of the tub is provided in plural, and the circumferential rib nearest to the center is thicker than other circumferential rib.
 9. The washing machine of claim 8, wherein the circumferential rib nearest to the center is formed in the same circumference as a circumference of a boss for allowing a stator fastened thereto.
 10. A tub of a washing machine comprising: a wall having a recessing part and a projecting part formed on an inner surface or an outer surface thereof in a circumferential direction, wherein a circumferential rib and a radial rib are formed on the recessing part; and a bearing housing inserted to the wall in injection-molding the tub, the bearing housing having a flange part. 